scholarly journals A comparative study on the effect of different activating solutions and formulations on the early stage geopolymerization process

2020 ◽  
Vol 322 ◽  
pp. 01039
Author(s):  
Lais Alves ◽  
Nordine Leklou ◽  
Silvio de Barros
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Early Stage ◽  
Construction Material ◽  
Potassium Hydroxide Solution ◽  
Mechanical And Thermal Properties ◽  
Liquid Ratio ◽  
Promising Alternative ◽  
Precursor Material ◽  
Activating Solution

Concrete is a major construction material that produces high levels of carbon dioxide in its manufacturing process. Hence the construction sector is responsible for relevant environmental impacts. This justifies the need to find materials as green and ecological alternatives to common Portland cement. Geopolymers represent the most promising alternative due to its proven durability, mechanical and thermal properties. This study investigates the effects of solid-to-liquid and alkali activator ratios on the synthesis of slag-based pure geopolymer and their relation to the geopolymerization process. Two activating solutions were used: a) a mixture of sodium hydroxide, sodium silicate, and water; and b) a mixture of potassium hydroxide solution, potassium silicate, and water. As precursor material, ground blast furnace slag was used. Precursors and activators were mixed with solid-to-liquid ratios in range of 1.5 to 2.2. In the first stage of the study, the mechanical properties were evaluated for each activating solution. In the following stage, different formulations, with variations in the water percentage and solid-to-liquid ratio were tested for mechanical properties and SEM observations. Test results indicate that the resulting geopolymer has the potential for high compressive strength and is directly affected by the composition of the activating solution. It can also be observed that compressive strength was affected by solid-to-liquid ratio and % of water added to the mixture, and strength increased with ageing day.

scholarly journals Influence of Glass Fibers on Mechanical Properties of Concrete with Recycled Coarse Aggregates

2019 ◽  
Vol 5 (5) ◽  
pp. 1007-1019 ◽  
Author(s):  
Babar Ali ◽  
Liaqat Ali Qureshi ◽  
Ali Raza ◽  
Muhammad Asad Nawaz ◽  
Safi Ur Rehman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Glass Fibers ◽  
Construction Material ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Highly Sensitive

Despite plain cement concrete presenting inferior performance in tension and adverse environmental impacts, it is the most widely used construction material in the world. Consumption of fibers and recycled coarse aggregates (RCA) can add ductility and sustainability to concrete. In this research, two mix series (100%NCA, and 100%RCA) were prepared using four different dosages of GF (0%GF, 0.25%GF, 0.5%GF, and 0.75%GF by volume fraction).  Mechanical properties namely compressive strength, splitting tensile strength, and flexural strength of each concrete mixture was evaluated at the age of 28 days. The results of testing indicated that the addition of GF was very useful in enhancing the split tensile and flexural strength of both RCA and NCA concrete. Compressive strength was not highly sensitive to the addition of GF. The loss in strength that occurred due to the incorporation of RCA was reduced to a large extent upon the inclusion of GF. GF caused significant improvements in the split tensile and flexural strength of RCA concrete. Optimum dosage of GF was determined to be 0.25% for NCA, and 0.5% for RCA concrete respectively, based on the results of combined mechanical performance (MP).

scholarly journals Expansion volume of alkali activated foamed cork composites from tungsten mining mud waste with aluminium

2019 ◽  
Vol 274 ◽  
pp. 03002
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes ◽  
Haroon Ihsan ◽  
John Pickstone ◽  
Nuno Estrada
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Mechanical And Thermal Properties ◽  
Porous Structures ◽  
Expansion Process ◽  
Foaming Agent ◽  
Al Powder ◽  
Highly Porous ◽  
Alkali Activated

Several mixes of alkali activated foams from tungsten mud waste (MW), grounded glass (GG) and metakaolin (MK) were developed incorporating expanded granulated cork (EGC). This study presents preliminary results of the expansion process obtained with the addition of aluminium (AL) powder as a foaming agent. 0.3 wt.%, 0.4 wt.% to 0.5wt.% of AL powder were added to the alkali activated matrix. The physical and mechanical properties of the obtained foams, the effects of the type and amount of the foaming agent added are presented and discussed. Highly porous structures were obtained, with overall expansion up to 68.2% when the AL powder was added. The size and distribution of pores are shown. The compressive strength of foams in the case of highly porous structures achieved of 1.2 MPa for the samples containing 0.5 wt.% of AL powder. Mechanical and thermal properties of the cured structure are good and can therefore be used for applications in acoustic panels and lightweight prefabricated components for thermal insulation purposes.

EFFECTS OF DIFFERENT SOURCES OF WATER ON THE PROPERTIES OF CONCRETE

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Ignatius Omuh ◽  
Rapheal Ojelabi ◽  
Adedeji Afolabi ◽  
Patience Tunji-Olayeni ◽  
Chukwuma Obi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
River Water ◽  
Potable Water ◽  
Tap Water ◽  
Construction Material ◽  
Well Water ◽  
Water Well ◽  
Concrete Mechanical Properties ◽  
Different Sources

Water is vital to human existence and life can only be sustained by it. Concrete is a widely used construction material and water is an important part of its composition. Potable water is what is recommended for concrete works, but unfortunately, some places do not have access to this. Places that do not have access to potable water might have access to other water sources that might be used for concrete works. This study was undertaken to investigate the effects of water from different sources on concrete mechanical properties. This study evaluates the characteristics of concrete produced with river water, well water, and potable tap water. Compressive strength and Density, were used to evaluate the characteristics of concrete specimens of mix ratios 1:2:4 and 1: 1 1/2 :3 produced with water from the different sources. The results showed that concrete specimens produced with tap water had the highest mean compressive strength at 28 days. While well water had the lowest compressive strength, it was concluded that well water was not suitable for concrete works even though it is already being used on some sites that can’t access tap water.

scholarly journals Investigation of the Effect of Addition Nano-papyrus Cane on the Mechanical Properties of Concrete

2021 ◽  
Vol 7 (2) ◽  
pp. 226-235
Author(s):  
Faisal K. Abdulhussein ◽  
Zahraa F. Jawad ◽  
Qais J. Frayah ◽  
ِAwham J. Salman
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Physical Properties ◽  
Construction Material ◽  
Dry Density ◽  
Split Tensile Strength ◽  
Maximum Enhancement ◽  
Concrete Mixtures ◽  
Traditional Construction

This paper investigates the effect of nano-papyrus cane ash as an additive on concretes’ mechanical and physical properties. Three types of concrete mixtures, 1:2:4, 1:1.5:3, and 1:1:2 were prepared for each mixture, nano-papyrus ash was added in five different dosages of 0.75, 1.5, 3, 4.5, and 6% by weight of cement; therefore, eighteen mixes would be studied in this work. Physical properties represented by dry density and slump were also measured for each mix. Moreover, to evaluate the mechanical properties development split tensile strength and compressive strength were obtained at age (7 and 28). Results manifested that the adding of nano ash developed the compressive strength and split tensile strength of concrete and the maximum enhancement recognized in the mixes with a content of 4.5% nano-papyrus in each studied mixture in this work. The slump test results indicated that the workability of concrete increased with adding nano-papyrus ash gradually with increasing nanoparticles' content. As well as, dry density was significant increased with nano-papyrus ratio; greater values were recorded in mixtures with 1.5-4.5% content of nano-papyrus. When comparing the concrete mixes used, it was found that the best results were obtained with 1:1:2 mixtures. This remarkable improvement in concrete properties considers the nano-papyrus is considered a cement economical and useful replacement for traditional construction material. Doi: 10.28991/cej-2021-03091649 Full Text: PDF

scholarly journals THE CONSTRUCTION OF A COMPOSITION BASED ON MAGNESIA BINDER WITH PEAT

Vestnik MGSU ◽  
2017 ◽  
pp. 642-646
Author(s):  
Natalia Shamilievna Lebedeva ◽  
Evgeniy Gennadievich Nedayvodin
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Compressive Strength ◽  
Building Material ◽  
Construction Material ◽  
Raw Material ◽  
Sound Insulation ◽  
Structural Purpose ◽  
Different Content ◽  
Good Heat

Obtained building material based on magnesia binder with different content of peat (0 to 90 %), on a specially developed technique. As a binder used PMK 87, for mixing mixtures used aqueous solution of magnesium chloride and peat from the Ivanovo region. It were determined such physical and physico-mechanical properties of the investigated material as the compressive strength and the density. The strength characteristics of silicate bricks, ceramic bricks and the investigated material based on magnesia binder and peat was analyzed and compared. It is established that the samples of construction material with content of peat not exceeding 40 wt.% can be attributed to the materials of structural purpose by its compressive strength. Samples of the material with content of the peat 40% have a density 943,75 kg/m3, that provides good heat and sound insulation properties. It is revealed that the solution of the raw material mixture of magnesia binder, peat, the solution of bischofite is optimized to place, and the material gets at least 85% of its strength during 30 days.

scholarly journals Mechanical Properties of Concrete Containing Liquefied Red Mud Subjected to Uniaxial Compression Loads

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 854 ◽  
Author(s):  
Gyeongcheol Choe ◽  
Sukpyo Kang ◽  
Hyeju Kang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Red Mud ◽  
Construction Material ◽  
Strain Curve ◽  
Peak Strain ◽  
Cement Type ◽  
Mixing Method ◽  
Relationship Of ◽  
The Relationship

This study used liquefied red mud (RM) sludge, an aluminum industry by-product, as a construction material. Accordingly, various methods were examined that used the fabricated liquefied red mud (LRM) as an admixture for concrete, and the mechanical properties of concrete were then evaluated according to the cement type and the amount of LRM. The LRM mixing methods (replacement and addition) were compared, and the slump and compressive strengths of concrete were evaluated for each method. To examine the mechanical properties according to the cement type and the amount of LRM, two types of cement (ordinary Portland cement and slag cement (SC)) were used, and 20 and 40 wt% LRM (with respect to the cement weight) were added. The mechanical properties of the stress–strain curve (SSC), compressive strength, peak strain, and elastic modulus were quantified. When the slump and compressive strength of concrete were considered based on the experimental results, the addition LRM mixing method was recommended as the appropriate method for LRM. As the addition of LRM increased, the mechanical properties of concrete degraded. However, when SC was used, the mechanical properties did not significantly change when different amounts of LRM were added (up to 20%). In addition, the SSC of LRM concrete could be approximated based on the use of the relationship of the compressive strength and peak strain according to the cement type and the amount of LRM.

scholarly journals The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1173 ◽  
Author(s):  
Češnovar ◽  
Traven ◽  
Horvat ◽  
Ducman
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Room Temperature ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Alkali Activation ◽  
Arc Furnace ◽  
Curing Time ◽  
Promising Alternative ◽  
Alkali Activated

Alkali activation is studied as a potential technology to produce a group of high performance building materials from industrial residues such as metallurgical slag. Namely, slags containing aluminate and silicate form a useful solid material when activated by an alkaline solution. The alkali-activated (AA) slag-based materials are promising alternative products for civil engineering sector and industrial purposes. In the present study the locally available electric arc furnace steel slag (Slag A) and the ladle furnace basic slag (Slag R) from different metallurgical industries in Slovenia were selected for alkali activation because of promising amorphous Al/Si rich content. Different mixtures of selected precursors were prepared in the Slag A/Slag R ratios 1/0, 3/1, 1/1, 1/3 and 0/1 and further activated with potassium silicate using an activator to slag ratio of 1:2 in order to select the optimal composition with respect to their mechanical properties. Bending strength of investigated samples ranged between 4 and 18 MPa, whereas compressive strength varied between 30 and 60 MPa. The optimal mixture (Slag A/Slag R = 1/1) was further used to study strength development under the influence of different curing temperatures at room temperature (R. T.), and in a heat-chamber at 50, 70 and 90 °C, and the effects of curing time for 1, 3, 7 and 28 days was furthermore studied. The influence of curing time at room temperature on the mechanical strength at an early age was found to be nearly linear. Further, it was shown that specimens cured at 70 °C for 3 days attained almost identical (bending/compressive) strength to those cured at room temperature for 28 days. Additionally, microstructure evaluation of input materials and samples cured under different conditions was performed by means of XRD, FTIR, SEM and mercury intrusion porosimetry (MIP).

scholarly journals Effects of Hollow Sizes on the Properties of Sandcrete Blocks

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
O.S. Olagunju ◽  
A.A. Raheem
Keyword(s):  
Mechanical Properties ◽  
Adverse Effect ◽  
Compressive Strength ◽  
Water Absorption ◽  
Mechanical Characteristics ◽  
Construction Material ◽  
African Countries ◽  
Wall Construction

Two-cell hollow sandcrete blocks constitute the dominant wall construction material for modern shelter in many African countries, especially Nigeria. The hollow cavities in the block have adverse effect on its mechanical characteristics. This study investigated the effects of hollow sizes on the properties of sandcrete blocks. Sandcrete blocks of size 225 × 225 × 450 mm with varying hollow sizes of 175 × 187.5, 173 ×190 and 180 × 210 mm and web thickness 25, 35 and 15 mm respectively; were produced using cement: sand ratio of 1:12. The blocks were tested for compressive strength, density and water absorption. The results indicated that compressive strength at 28 days for blocks with hollow sizes 175 × 187.5, 173 ×190 and 180 × 210 mm are 5.22, 3.64 and 0.41 Nmm-2 respectively. The corresponding densities are 2307.56, 2589.15 and 1715.23 kg/m³ while the rate of water absorption are 22.2, 18.8 and 24.5%, respectively. It was concluded that the larger the size of the hollow in sandcrete blocks the lower their mechanical properties.

scholarly journals Rice Husk Ash-Based Geopolymer Binder: Compressive Strength, Optimize Composition, FTIR Spectroscopy, Microstructural, and Potential as Fire-Retardant Material

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4373
Author(s):  
Mohd Salahuddin Mohd Basri ◽  
Faizal Mustapha ◽  
Norkhairunnisa Mazlan ◽  
Mohd Ridzwan Ishak
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Material ◽  
Fire Retardant ◽  
Major Effect ◽  
Material Behavior ◽  
Promising Alternative ◽  
Fire Retardant Properties ◽  
Geopolymer Binder

Compressive strength is an important property in construction material, particularly for thermal insulation purposes. Although the insulation materials possess high fire-retardant characteristics, their mechanical properties are relatively poor. Moreover, research on the correlation between fire-retardant and compressive strength of rice husk ash (RHA)-based geopolymer binder (GB) is rather limited. In addition, previous studies on RHA-based GB used the less efficient one-factor-at-a-time (OFAT) approach. In understanding the optimum value and significant effect of factors on the compressive strength, it was deemed necessary to employ statistical analysis and a regression coefficient model (mathematical model). The objective of the study is to determine the effect of different material behavior, namely brittle and ductile, on the compressive strength properties and the optimum material formulation that can satisfy both compressive strength and fire-retardant properties. The factors chosen for this study were the rice husk ash/activated alkaline solution (RHA/AA) ratio and the sodium hydroxide (NaOH) concentration. Compressive strength and fire-retardant tests were conducted as part of the experiments, which were designed and analyzed using the response surface methodology (RSM). The microstructure of geopolymer samples was investigated using a scanning electron microscope (SEM). Results showed that RHA/AA ratio was highly significant (p < 0.000) followed by NaOH concentration (p < 0.024). When the RHA/AA ratio was at 0.7 to 0.8 and the NaOH concentration was between 12 and 14 M, high compressive strength above 28 MPa was recorded. Optimum compressive strength of approximately 47 MPa was achieved when the RHA/AA ratio and NaOH concentration were 0.85 and 14 M, respectively. Brittle samples with low Si/Al ratio of 88.95 were high in compressive strength, which is 33.55 MPa, and showed a high degree of geopolymerization. Inversely, ductile samples showed low compressive strength and degree of geopolymerization. Water content within the geopolymer binder had a major effect on its fire-retardant properties. Semi-ductile GB showed the best fire-retardant properties, followed by semi-brittle and brittle GB. Using RHA as an aluminosilicate source has proven to be a promising alternative.

The Study of BP Neural Network in Predicting Concrete Strength

2011 ◽  
Vol 243-249 ◽  
pp. 6169-6173
Author(s):  
Zhao Ming
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Bp Neural Network ◽  
Construction Material ◽  
Concrete Strength ◽  
Main Criterion ◽  
The Past ◽  
Compressive Strength Of Concrete ◽  
Test Result

Concrete is a mainly and commonly good combined construction material, and is consisted of many well-defined components, so mechanical properties of concrete are very complex. the compressive strength of the concrete is a main criterion in producing concrete, but the test on it is complicated because test components of concrete must be kept in the special condition an tested after 28 days. To simplify the procedures and obtain a reasonable data, the paper presents a method using the system of BP neural network predicting the strength of concrete. the system is trained and tested by using many data of strength of concrete in the past ,the test result shows that the value of the strength of concrete predicted is approximate to the experimental value, and the method presented is very efficient and reasonable in predicting the compressive strength of concrete .

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